Morphology is the study of word structure and formation. It involves the analysis of morphemes like roots, affixes, and stems. There are two main types of morphemes - inflectional morphemes which mark grammatical functions and derivational affixes which can change word categories. Some common word formation processes in English include affixation, compounding, clipping, blending, borrowing, back-formation, and functional shift. Morphemes can be categorized as root morphemes, which have an individual lexical meaning, or non-root morphemes like inflections and affixes.